Asia must act now to pave the way for green, resource-friendly cities or face a bleak and environmentally degraded future, says a new Asian Development Bank (ADB) report.

“Asia has seen unprecedented urban population growth but this has been accompanied by immense stress on the environment,” said Changyong Rhee, ADB’s Chief Economist.

“The challenge now is to put in place policies which will reverse that trend and facilitate the development of green technology and green urbanization.”

In a special chapter of its flagship annual statistical publication, Key Indicators for Asia and the Pacific 2012, ADB examines the challenges and opportunities associated with the region’s breakneck urban boom. It also details measures needed to turn cities into environmentally sustainable, inclusive growth centers.

Since the 1980s, Asia has been urbanizing at a faster rate than anywhere else, with the region already home to almost half of all the world’s city dwellers.

In just over a decade, it will have 21 of 37 megacities worldwide, and over the next 30 years another 1.1 billion people are expected to join Asia’s already swollen urban ranks.

This breakneck expansion has been accompanied by a sharp rise in pollution, slums, and widening economic and social inequalities which are causing rapid environmental degradation.

Particularly disturbing are urban carbon dioxide emissions

which if left unchecked under a business-as-usual scenario, could reach 10.2 metric tons per capita by 2050, a level which would have disastrous consequences for both Asia and the rest of the world.

Rising urban populations mean that over 400 million people in Asians cities may be at risk of coastal flooding and roughly 350 million at risk of inland flooding by 2025.

Unless managed properly, these trends could lead to widespread environmental degradation and declining standards of living.

The report notes that there is hope. The growth of cities can have many advantages, including critical masses of people in relatively small areas, making it easier and more cost effective to supply essential services like piped water and sanitation.

Like Bangkok, most major cities sit on coasts, straddle rivers, or lie on vulnerable deltas, putting them on the front line of rising sea levels and flooding in the coming decades.

Rising education levels, factories leaving cities, the growth of middle classes and declining birth rates typically associated with urbanization also have a broadly beneficial impact on resource use and the environment.

Conservation and efficiency improvements will help. Many countries have begun diversifying their energy sources to include renewables and have been investing in energy-efficient buildings and sustainable transport systems.

Imposing congestion and emission charges, as in Singapore, and removing inefficient fuel subsidies, as in Indonesia, can make prices more fully reflect social costs. But the report says much more is needed, including the development and mainstreaming of new green technologies. Early examples are waste-to-energy conversion plants, as in the Philippines and Thailand, or “smart” electric grids.

For urbanization to be not only green but inclusive, policy makers need to promote climate resilient cities, in order to prevent disasters like the 2011 Bangkok floods, and improve urban slum areas, the report points out.

via Asia’s Booming Cities Must Go Green or Risk Disaster – ADB Study | Asian Development Bank.